US4068138A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Signal converter
Assignee: Hitachi Ltd
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Filing: 1976-05-17
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Granted: 1978-01-10
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Expires: 1996-05-17
Abstract
Abstract A signal converter for converting a varying input voltage, such as an output signal from a detector, into an output voltage in absolute value, including an operational amplifier, a comparator and two groups of electronic switches. The comparator compares the varying input voltage to a predetermined reference voltage. The operational amplifier has negative and positive input terminals and generates an output voltage signal in proportion to the difference between the voltages applied to its two input terminals. When the input voltage is less than the reference voltage, one group of electronic switches turns on, so that the input voltage and the reference voltage are applied to the negative and the positive input terminals of the operational amplifier, respectively. When the input voltage is greater than the reference voltage, the other group of the electronic switches turns on, so that the input voltage and the reference voltage are applied to the positive and the negative input terminals of the operational amplifier, respectively.
Inventors
- 👤 Nobuaki Miyakawa
- 👤 Osamu Igarashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 19:37
CPC Classifications
G; G01; G01D; G01D3/00; G01D3/02; G01K; G01K7/00
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
145 words
A signal converter for converting a varying input signal into an output signal of absolute value comprising reference voltage producing means for generating a predetermined reference voltage value; comparing means responsive to said input signal and said predetermined reference voltage value for generating a control signal having first and second values indicating whether said input signal is greater or less than said reference voltage value, respectively; an operational amplifier circuit having first and second input terminals; and switching means responsive to said control signal for applying said input signal and said reference voltage value to said first and second input terminals of said operational amplifier, respectively, when said control signal has said first value, and for applying said input signal and said reference voltage value to said second and first input terminals of said operational amplifier, respectively, when said control signal has said second value.
Claim 2
Dependent Claim
145 words
A signal converter for converting a varying input signal into an output signal of absolute value comprising reference voltage producing means for generating a predetermined reference voltage value; comparing means responsive to said input signal and said predetermined reference voltage value for generating a control signal having first and second values indicating whether said input signal is greater or less than said reference voltage value, respectively; an operational amplifier circuit having first and second input terminals; and switching means responsive to said control signal for applying said input signal and said reference voltage value to said first and second input terminals of said operational amplifier, respectively, when said control signal has said first value, and for applying said input signal and said reference voltage value to said second and first input terminals of said operational amplifier, respectively, when said control signal has said second value.
Claim 3
Dependent Claim
19 words
A signal converter as claimed in claim 1, wherein said reference voltage producing means includes a variable voltage source.
Claim 4
Dependent Claim
35 words
A signal converter as claimed in claim 1, wherein said operational amplifier circuit has two different gains which are switched over by said switching means in response to the control signal from the comparing means.
Claim 5
Dependent Claim
43 words
A signal converter as claimed in claim 1, wherein said comparing means includes a comparator circuit having first and second inputs receiving said input signal and said reference voltage value, respectively, and an inverter circuit connected to the output of said comparator circuit.
Claim 6
Dependent Claim
44 words
A signal converter as claimed in claim 4, wherein said switching means includes first means responsive to the output of said comparator circuit for applying said input signal and said reference voltage value to said first and second input terminals of said operational amplifier.
Claim 7
Dependent Claim
45 words
A signal converter as claimed in claim 5, wherein said switching means further includes second means responsive to the output of said inverter circuit for applying said reference voltage value and said input signal to said first and second input terminals of said operational amplifier.
Claim 8
Dependent Claim
48 words
A signal converter as claimed in claim 6, wherein said first means includes first and second switches which are operated when said control signal has said first value, and said second means includes third and fourth switches which are operated when said control signal has said second value.
Claim 9
Dependent Claim
53 words
A signal converter as defined in claim 7, wherein said second and fourth switches are each connected to one of a voltage divider comprising first and second resistors connected in series, the point of connection of said first and second resistors being connected to the second input terminal of said operational amplifier circuit.
Claim 10
Dependent Claim
66 words
A signal converter as defined in claim 7, wherein said second switch is connected to one end of a voltage divider comprising first and second resistors connected in series, said fourth switch being connected in series with a third resistor to the point of connection of said first and second resistors which, in turn, is connected to the second input terminal of said operational amplifier circuit.
Claim 11
Dependent Claim
49 words
A signal converter as defined in claim 7, wherein said reference voltage producing means includes a first and second variable reference voltage source, said first reference voltage source being connected to said comparing means and said third switch, said second reference voltage source being connected to said second switch.
Claim 12
Dependent Claim
42 words
A signal converter as defined in claim 4, further including state indicating means responsive to the outputs of said comparator circuit and said inverter circuit for providing a visual indication of whether said control signal has a first or a second value.
Claim 13
Dependent Claim
28 words
A signal converter as claimed in claim 1, wherein said reference voltage producing means generates a predetermined reference voltage value having a predetermined value with respect to ground.
Claim 14
Dependent Claim
32 words
A signal converter as claimed in claim 10, wherein said first reference voltage source includes a variable resistor for applying said reference voltage value to an input terminal of said comparing means.
References Cited (Backward Citations)
US3502905A
Cited
US3882327A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-01-09 | 1981-07-11 | 1982-01-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-01-09 | 1985-07-11 | 1986-01-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-01-09 | 1989-07-11 | 1990-01-10 | $7700.00 | Window Closed / Lapsed |